Right now, let's get to the mechanics of a limited air attack. This one should probably really have a random out-of-the-players' hands feel to it. Neil Smith recommended a random events table in his "Skirmish Envelope" article in WI 259 and I think this may be the right way to bring in air attacks into a skirmish game. The scenario designer/referee can certainly tweak the probabilities of having air support arrive as well as WHOSE air support arrives. Of course, there's such vagaries as misidentifying aircraft and troops on the ground by both parties, so there's a chance to throw in some friendly fire into the mix.
Frankly, I think all of the above concerns are big IFs and I suppose the designer can make them as simple, complicated, or random as desired. The most devious thing I could think would be to have a plane show up - doesn't matter whose side it is on - and make a random check (you might could weight the probability for one side or the other) for what section, gun team, or vehicle takes a pounding with bombs or rockets - and it might be worth clarifying a priority target list here as well. Simply use mortar or artillery templates for effects.
Offhand, I would recommend that a strafing attack simply require a tape measure, yard stick, or wooden dowel to be placed at the selected attack point and set across the table as desired. The kill zone could probably measure 2 or 3 inches on either side (giving a 4 - 6 inch swath of destruction), with a knockdown or pin zone of equal distance beyond. I guess 3 feet would be about the extent of the strafing run, but 2 feet might work as well; I think 12" seems a bit short, but I suppose it would be worth researching minimum strafing fields of fire before coming down against it.
Now I suppose if you decide on using the random ground attack method mentioned previously the referee could use scatter dice to determine the axis of the strafing run. This could certainly result in attacks on both sides.
To represent a strafing attack, I suppose you could use a scale model of a suitable aircraft. If we assume that 1 inch represents about 5 feet, then it's probably not too crazy to have the model suspended over the tabletop by 18" or 24" (90 or 120 feet altitude) - which seems close to treetop level. You could also put them in at an angle. I would say that attack/descent altitude be handled abstractly by ground fire - ie. the plane isn't actually 18" above them. Offhand, I'd say any AA weapons should treat strafing aircraft as medium or long range shots (and assuming they aren't surprised and can react).
Alternately, I think it might be kind of cool to make a silhouette out of card of foamcore and place it directly on the table. I think this even more appropriate if you are handling a bombing action. I'm taking a nod from the Combat Mission computer game here - whenever aircraft show up, you just see passing shadows - and there's always a chance of friendly fire.
All right, that's it for today. Next time around we'll take a look at some historical data on Luftwaffe air-to-ground attacks and see how that can play a role in scenario design.